This is a collection of Intel®’ IA32® Software Developer's Manuals (URL of the day) and AMD' AMD64 Architecture Programmer's Manual together with the related specifications, application notes, white papers, and change logs. The collection aims to keep all available revisions. It was originally created by Michal Necasek, see OS/2 Museum.

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SXTB

Signed Extend Byte extracts an 8-bit value from a register, sign-extends it to 32 bits, and writes the result to the destination register. The instruction can specify a rotation by 0, 8, 16, or 24 bits before extracting the 8-bit value.

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 and T2 ) .

A1

Decode for this encoding

let d : integer = UInt(Rd); let m : integer = UInt(Rm); let rotation : integer = UInt(rotate::'000'); if d == 15 || m == 15 then UnpredictableProcedure(); end;

T1

Decode for this encoding

let d : integer = UInt(Rd); let m : integer = UInt(Rm); let rotation : integer = 0;

T2

Decode for this encoding

let d : integer = UInt(Rd); let m : integer = UInt(Rm); let rotation : integer = UInt(rotate::'000'); // Armv8-A removes UNPREDICTABLE for R13 if d == 15 || m == 15 then UnpredictableProcedure(); end;

Assembler Symbols